A diode laser component is an arrangement consisting of at least one diode laser or a diode laser arrangement with several diode lasers or emitters and a cooling element. In addition, in the diode laser component there can also be other components, for example, for triggering the diode laser or diode laser arrangement.
Multilayer cooling arrangements or cooling systems for electrical and electronic components are known, especially heat sinks for high power laser diodes or high power laser diode arrangements (U.S. Pat. No. 5,105,430).
In known cooling systems, cooling channels are formed in stacked layers through which a liquid cooling medium flows, for example water. These channels are typically microchannels which are formed in the layers in the immediate vicinity of the component to be cooled by three dimensional microstructures. This improves the cooling action by providing a surface which is as large as possible that comes into contact with the cooling medium. Using this heat sink can reduce the heat resistance by a factor of 2-5 relative to a convention conductive cooler.
Thus, for example, a cooling arrangement is known with a circulating cooling medium for cooling of solid-state diode lasers (U.S. Pat. No. 5,105,430) in which the component to be cooled is joined both electrically and thermally to the cooler. Microchannels are formed under the solid-state component. Feed and drain channels are in the cooling element for supply and removal.
Furthermore, an arrangement is known in which a large area cooler is produced by a host of microchannels under the surface to be cooled (U.S. Pat. No. 5,099,910). The particular feature in this known arrangement is the special form of meandering coolant guidance through the microchannels. The arrangement is generally suitable for cooling electronic components.
A cooling arrangement is known (U.S. Pat. No. 4,573,067) which is designed especially for compact integrated circuits. To increase the cooling and heat exchanger surface, cooling rods are housed in a chamber through which the cooling medium flows.
Finally, a cooling arrangement (U.S. Pat. No. 4,516,632) having a cross flow heat exchanger consisting of several structured sheets placed on top of one another is known.
The disadvantage in the known diode laser components or their coolers is that to achieve heat dissipation as efficient as possible they use microchannels, i.e., channels with a width less than 100 microns, and require relatively expensive production. In addition, the different coefficients of expansion of the cooling element and the chip material of the component to be cooled are ignored and the mechanical strength and possibilities of current feed are not optimally resolved.
Known cooling elements require, if the coolers are metallic and conductive, additional insulating foils for insulation or potential separation of the electrical components, especially between the anode and cathode of a diode laser. An additional difficulty arises when this insulating film, if it has a sealing function relative to the cooling medium, is deformed by the pressure of the cooling medium. For this reason, stresses in the solid-state component to be cooled are inevitable. They lead to premature damage of the solid-state component, such as the solid-state diode chip.
It is necessary to galvanically apply conductive layers as contact layers and printed conductors for reconductive coolers. These galvanically applied layers, however, generally have only very small thicknesses. Major ohmic losses occur and high current densities in the conductive layers are not possible, since they can lead to metallurgical alteration of the conductive layers, i.e., the printed conductors and contact surfaces.
Attempts have been made to match the coefficient of expansion of the cooling element to the coefficient of expansion of the chip material of the solid state-component, for instance, the coefficient of expansion of GaAs in solid-state diode lasers, by a corresponding choice of material. The materials to be considered here, however, have relatively low thermal conductivities.
The disadvantage in known metallic cooling elements having thin metal layers or metal foils is that the resistance of these cooling components to mechanical deformations is not very great. During or after an assembly process deformations are possible which then lead to stresses in the solid-state components provided on the cooling element and thus to a reduction of the service life of this component.
The object of the invention is to devise a diode laser component which avoids the disadvantages of known diode laser components and their cooling elements with the possibility of simple manufacture of the cooling element and optimum cooling action.